<?php

// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace Think\Cache\Driver;

use Think\Cache;

defined('THINK_PATH') or exit();

/**
 * Memcache缓存驱动
 * @category   Extend
 * @package  Extend
 * @subpackage  Driver.Cache
 * @author    liu21st <liu21st@gmail.com>
 */
class Memcachesae extends Cache {

    /**
     * 架构函数
     * @param array $options 缓存参数
     * @access public
     */
    function __construct($options = array()) {
        if (empty($options)) {
            $options = array(
                'host' => C('MEMCACHE_HOST') ? C('MEMCACHE_HOST') : '127.0.0.1',
                'port' => C('MEMCACHE_PORT') ? C('MEMCACHE_PORT') : 11211,
                'timeout' => C('DATA_CACHE_TIMEOUT') ? C('DATA_CACHE_TIMEOUT') : false,
                'persistent' => false,
            );
        }
        $this->options = $options;
        $this->options['expire'] = isset($options['expire']) ? $options['expire'] : C('DATA_CACHE_TIME');
        $this->options['prefix'] = isset($options['prefix']) ? $options['prefix'] : C('DATA_CACHE_PREFIX');
        $this->options['length'] = isset($options['length']) ? $options['length'] : 0;
        //  $func               =   isset($options['persistent']) ? 'pconnect' : 'connect';
        $this->handler = memcache_init(); //[sae] 下实例化
        //[sae] 下不用链接
        $this->connected = true;
        // $this->connected    =   $options['timeout'] === false ?
        //     $this->handler->$func($options['host'], $options['port']) :
        //     $this->handler->$func($options['host'], $options['port'], $options['timeout']);
    }

    /**
     * 是否连接
     * @access private
     * @return boolean
     */
    private function isConnected() {
        return $this->connected;
    }

    /**
     * 读取缓存
     * @access public
     * @param string $name 缓存变量名
     * @return mixed
     */
    public function get($name) {
        N('cache_read', 1);
        return $this->handler->get($_SERVER['HTTP_APPVERSION'] . '/' . $this->options['prefix'] . $name);
    }

    /**
     * 写入缓存
     * @access public
     * @param string $name 缓存变量名
     * @param mixed $value  存储数据
     * @param integer $expire  有效时间（秒）
     * @return boolean
     */
    public function set($name, $value, $expire = null) {
        N('cache_write', 1);
        if (is_null($expire)) {
            $expire = $this->options['expire'];
        }
        $name = $this->options['prefix'] . $name;
        if ($this->handler->set($_SERVER['HTTP_APPVERSION'] . '/' . $name, $value, 0, $expire)) {
            if ($this->options['length'] > 0) {
                // 记录缓存队列
                $this->queue($name);
            }
            return true;
        }
        return false;
    }

    /**
     * 删除缓存
     * @access public
     * @param string $name 缓存变量名
     * @return boolean
     */
    public function rm($name, $ttl = false) {
        $name = $_SERVER['HTTP_APPVERSION'] . '/' . $this->options['prefix'] . $name;
        return $ttl === false ?
                $this->handler->delete($name) :
                $this->handler->delete($name, $ttl);
    }

    /**
     * 清除缓存
     * @access public
     * @return boolean
     */
    public function clear() {
        return $this->handler->flush();
    }

    /**
     * 队列缓存
     * @access protected
     * @param string $key 队列名
     * @return mixed
     */
    //[sae] 下重写queque队列缓存方法
    protected function queue($key) {
        $queue_name = isset($this->options['queue_name']) ? $this->options['queue_name'] : 'think_queue';
        $value = F($queue_name);
        if (!$value) {
            $value = array();
        }
        // 进列
        if (false === array_search($key, $value))
            array_push($value, $key);
        if (count($value) > $this->options['length']) {
            // 出列
            $key = array_shift($value);
            // 删除缓存
            $this->rm($key);
            if (APP_DEBUG) {
                //调试模式下记录出队次数
                $counter = Think::instance('SaeCounter');
                if ($counter->exists($queue_name . '_out_times'))
                    $counter->incr($queue_name . '_out_times');
                else
                    $counter->create($queue_name . '_out_times', 1);
            }
        }
        return F($queue_name, $value);
    }

}
